The present invention relates to a system for storing a plurality of recording mediums in a reproducing system, and more particularly to a storing system having a plurality of rotary circular racks wherein a plurality of discs such as CDs are stored.
A disc reproducing system having an automatic disc changer has recently become popular. The disc reproducing system is provided with a rack wherein a large number of CDs are stored so as to improve the storing efficiency of the CDs.
Referring to FIG. 15 showing one of these conventional reproducing systems, having a rotary circular rack 40, a disc reproducing system 10 has a chassis 20 on which a roulette device 30 is mounted. The roulette device 30 comprises a base 31 on which a circular rack base 32 having a spindle 33 is mounted. The circular rack 40 having a plurality of radial slits 45 is rotatably mounted on the spindle 33. A twelve-centimeter CD 200 or an eight-centimeter CD (not shown) is held in each slit 45. A disc player 70 having an arm 72 for loading the CD 200 into the player 70 is further mounted on the base 31.
The roulette device 30 and the disc player 70 are covered by a casing 90, rear panel 100, and a front operation panel 110 which are securely mounted on the chassis 20. The operation panel 110 has an opening 111 through which CDs can be exchanged. The opening 111 is covered by an arcuated door 60 having a sector shaped top. The door 60 is rotatably mounted on a center post 50, which is mounted on the spindle 33 of the rack base 32, at the angle of the sector-shaped top.
Referring to FIG. 16, the rack 40 has an encoder 170 on the underside thereof. The encoder 170 comprises an outer ring 171 and an inner ring 172. The outer ring 171 has a plurality of slits 174 equiangularly formed in the entire circumference of the ring except for an area called a home position H corresponding to an area where slits 45 are not formed on the upper side of the rack. Each slit 174 corresponds to one of the slits 45. The inner ring 172 has nine light blocking projections 173A to 173I and nine slits 173a to 173i formed between the blocking projections. The widths of the slits 173a to 173i increase gradually starting from the home position H in the clockwise direction as shown in FIG. 16.
An optical sensor 179C comprising a first set of light emitting element 175 and light receiving element 176 and a second set of light emitting element 177 and light receiving element 178 are mounted on the base 31 adjacent the encoder 170. As the rack 40 is rotated, the light from the light emitting element 175 is applied to the light receiving element 176, thereby generating pulses, each pulse corresponding to the slit 174 of the outer ring 171. The light from the light emitting element 177 is applied to the light receiving element 178 thereby generating pulses, each pulse width corresponding to each of the slits 173a to 173i of the inner ring 172. The angular position of the rack 40 can thus be determined by detecting the combination of the pulses.
Since the slits 174 are not formed in the home position H, when the sensor 179C faces the home position, pulses are not generated.
The disc reproducing system 10 is operated by operating various buttons (not shown) formed on the operating panel 110. When a select button is depressed to select one of the CDs 200 to be played, the rack 40 is rotated. The angular position of the rack 40 is detected by the encoder 170 and the optical sensor 179C so that the rotation of the rack 40 is stopped when the slit 45 storing the selected CD 200 is at the loading position directly opposite the disc player 70. Thereafter, the arm 72 projecting out from the disc player 70 is inserted into the slit 45 from the underside of the rack 40 and engages the CD 200. The arm 72 is further rotated to carry the CD 200 in the slit 45 into the player 70.
In such a disc reproducing system, the CDs are radially stored in the circular rack 40 so that the storing efficiency is improved.
Although the slits 174 are not formed in the home position H, it is possible to detect the slit 45 at the loading position if the optical sensor 179C is disposed adjacent the disc player 70, thereby directly detecting the slit 45 opposite the disc player 70, that is at the loading position.
However, the angular position of the rack 40 must also be detected when exchanging the CDs in the rack with other CDs. Namely, it is necessary to detect the slits 45 which face the opening 111 of the operation panel 110. If the rack 40 is at a position where the optical sensor 179C is within the home position, it is impossible to detect the slits 45 confronting the opening 111.
In order to further improve the storing efficiency of the CDs, it is desirable that the conventional disc reproducing system 10 of FIG. 15 is modified so that a plurality of racks 40 are vertically tiered. For the sake of restraining the manufacturing cost, it is preferable that only one disc player 70 is provided, and the player is arranged to vertically move for playing a CD stored in any of the racks 40. In order to allow the disc player 70 to freely move without interference from the racks 40, the disc player 70 is firstly withdrawn away from the racks 40. The disc player 70 is then vertically moved to the height of a particular rack 40 storing the selected CD. After the rack 40 is rotated to a position where the slit 45 of the selected CD faces the disc player 70, the disc player 70 is advanced so as to carry the CD from the rack 40 into the player 70.
However, such a system requires additional operations such as retreat, vertical movement and the advance of the disc player 70 so that, not only does the operating mechanism become complicated, there must be provided an additional space for moving the disc player 70. Hence, such a modification is disadvantageous from the point of reducing the manufacturing cost and decreasing the size of the system.
In order to solve the problem, it is necessary to provide a recess having a sufficient dimension in each of the racks 40, so that the disc player 70 may vertically pass through without the arm 72 or any other parts of the player getting caught by the rack 40. Thus the disc player 70 no longer needs to move in the horizontal plane and the mechanism for moving the disc player 70 is much simplified, thereby enabling to reduce the manufacturing cost and to decrease size of the system.
When such a recess is formed in the rack 40, the area where the CDs cannot be stored is increased. As a result, the area of the home position of the encoder 170 is also increased. The slit 45 at the loading position can still be determined as described above when the optical sensor 179C is disposed to confront the disc player 70. However, slits 45 facing the opening 111 of the operation panel 110 cannot be determined when the sensor 179c happens to be at the home position.
Another problem which arises concerns a locking device of the rack 40. The rack 40 must be locked so as not to rotate while the CD is carried toward the disc player 70. The locking means, for example, comprises a lock pin provided on the disc player 70 so as to be projected, and a plurality of receptacles formed on the periphery of the rack 40 to which the lock pin engages. When the angular position of the rack is determined so that a particular slit 45 opposes the disc player 70, the pin of the disc player 70 engages with the receptacle adjacent the slit, thereby preventing the rotation of the rack. However, receptacles cannot be formed in the area where the recess for allowing the vertical movement of the disc player is cut out. Accordingly, the rack 40 cannot be locked when disposed in certain positions.